class_docstr: test GridspecLayout
docstr: test retrieving widget
docstr_tok: ["test","retrieving","widget"]
code: def test_getitem_index(self):
      "test retrieving widget"
  
      box = widgets.GridspecLayout(2, 3)
      button1 = widgets.Button()
  
      box[0, 0] = button1
  
      assert box[0, 0] is button1
  
imports: from unittest import TestCase
  import pytest
  import traitlets
  import ipywidgets
  from ipywidgets.widgets.widget_templates import LayoutProperties
label_desc: Use image node_id 4 for calling the TestGridspecLayout obj's underlying member method code with example usage: obj.test_getitem_index() without return types